reverse transcriptaseAny of a class of enzymes that catalyze the formation of DNA from an RNA template and are found in retroviruses, and also in certain body cells (such as stem cells) as the enzyme telomerase. The action of reverse transcriptase runs in the opposite direction from normal genetic transcription in the cell, in which RNA is copied from DNA. Drugs that inhibit the action of viral reverse transcriptase have been used to treat retroviral infections such as AIDS, and those that inhibit telomerase are potential anticancer agents.